This specification relates to identifying terms, e.g., spam terms within a collection of documents.
In the context of web mapping services, the owners of a business can attempt to attract customers by creating fake instances of their business in geographic locations where their business does not actually exist. These fake instances of a business, which are referred to by this specification as “map spam,” may appear on a map interface generated by the web mapping service when a user searches for a business, and may drive traffic to an online- or telephone-based sales channel for the business. In general, businesses which practice map spamming rely on the fact that, when a user performs a search using a web mapping service to identify nearby businesses, the user may not reconfirm whether the business is actually located in an identified location.
As an example of map spam, a plumbing business may submit information to a web mapping service to indicate that the plumbing business has a brick-and-mortar presence on every block along a street. A user that lives along the street may search for a nearby plumber using the web mapping service when, for example, the user requires emergency plumbing service. Using the information that the plumbing business has provided, the web mapping service may display a map that shows that the plumbing business is near to the user, and may display a telephone number or web address of the plumbing business. Comforted by the fact that the plumbing business appears to be nearby, the user may contact the plumbing business for service, even though the plumbing business may in fact be located a great distance away, and other plumbing business may actually be located closer to the user.
Map spam may be detrimental to many different parties. For example, map spam harms the provider of the web mapping service because the information provided to the users is inaccurate, rendering the web mapping service's databases untrustworthy. Map spam harms users, who may experience delays when dealing with a business that is located farther from the user than is represented. Moreover, map spam harms local businesses, who may suffer a loss of business when local customers are diverted to faraway businesses, because of the faraway businesses' misleading listings.